Added three more sites

tidwall · Sep 4, 2020 · caafade · caafade
1 parent 251f94f
commit caafade
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Showing 2 changed files with 42 additions and 37 deletions.
diff --git a/README.md b/README.md
@@ -4,7 +4,7 @@
 
 Retrieve the current time from remote servers.
 
-It works by requesting timestamps from nine very popular hosts over https.
+It works by requesting timestamps from twelve very popular hosts over https.
 As soon as it gets at least three responses, it takes the two that have the
 smallest difference in time. And from those two it picks the one that is
 the oldest. Finally it ensures that the time is monotonic.

diff --git a/rtime.go b/rtime.go
@@ -10,7 +10,7 @@ import (
 var sites = []string{
 	"facebook.com", "microsoft.com", "amazon.com", "google.com",
 	"youtube.com", "twitter.com", "reddit.com", "netflix.com",
-	"bing.com",
+	"bing.com", "twitch.tv", "myshopify.com", "wikipedia.org",
 }
 
 var rmu sync.Mutex
@@ -26,6 +26,10 @@ var rtime time.Time
 //    }
 //
 func Now() time.Time {
+	start := time.Now()
+	defer func() {
+		println(time.Since(start).String())
+	}()
 	res := make([]time.Time, 0, len(sites))
 	results := make(chan time.Time, len(sites))
 
@@ -55,46 +59,47 @@ func Now() time.Time {
 			return time.Time{}
 		case tm := <-results:
 			res = append(res, tm)
-
-			if len(res) >= 3 {
-				// We must have a minimum of three results. Find the two of three
-				// that have the least difference in time and take the smaller of
-				// the two.
-				type pair struct {
-					tm0  time.Time
-					tm1  time.Time
-					diff time.Duration
-				}
-				var list []pair
-				for i := 0; i < len(res); i++ {
-					for j := i + 1; j < len(res); j++ {
-						if i != j {
-							tm0, tm1 := res[i], res[j]
-							if tm0.After(tm1) {
-								tm0, tm1 = tm1, tm0
-							}
-							list = append(list, pair{tm0, tm1, tm1.Sub(tm0)})
+			if len(res) < 3 {
+				continue
+			}
+			// We must have a minimum of three results. Find the two of three
+			// that have the least difference in time and take the smaller of
+			// the two.
+			type pair struct {
+				tm0  time.Time
+				tm1  time.Time
+				diff time.Duration
+			}
+			var list []pair
+			for i := 0; i < len(res); i++ {
+				for j := i + 1; j < len(res); j++ {
+					if i != j {
+						tm0, tm1 := res[i], res[j]
+						if tm0.After(tm1) {
+							tm0, tm1 = tm1, tm0
 						}
+						list = append(list, pair{tm0, tm1, tm1.Sub(tm0)})
 					}
 				}
-				sort.Slice(list, func(i, j int) bool {
-					if list[i].diff < list[j].diff {
-						return true
-					}
-					if list[i].diff > list[j].diff {
-						return false
-					}
-					return list[i].tm0.Before(list[j].tm0)
-				})
-				res := list[0].tm0.Local()
-				// Ensure that the new time is after the previous time.
-				rmu.Lock()
-				defer rmu.Unlock()
-				if res.After(rtime) {
-					rtime = res
+			}
+			sort.Slice(list, func(i, j int) bool {
+				if list[i].diff < list[j].diff {
+					return true
+				}
+				if list[i].diff > list[j].diff {
+					return false
 				}
-				return rtime
+				return list[i].tm0.Before(list[j].tm0)
+			})
+			res := list[0].tm0.Local()
+			// Ensure that the new time is after the previous time.
+			rmu.Lock()
+			defer rmu.Unlock()
+			if res.After(rtime) {
+				rtime = res
 			}
+			println(time.Now().Sub(rtime).String())
+			return rtime
 		}
 	}
 }